watchdog: coh901327: convert to use watchdog core

This converts the COH901327 watchdog to use the watchdog core.
I followed Wolframs document, looked at some other drivers and
tested it on the U300.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 7a88953..e25a464 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -287,6 +287,7 @@
 	bool "ST-Ericsson COH 901 327 watchdog"
 	depends on ARCH_U300
 	default y if MACH_U300
+	select WATCHDOG_CORE
 	help
 	  Say Y here to include Watchdog timer support for the
 	  watchdog embedded into the ST-Ericsson U300 series platforms.